Is Black Licorice Bad for You?

How much black licorice is too much—and can it have some health benefits when eaten in moderation?

In 2017, the Food and Drug Administration (FDA) reported that eating two ounces of black licorice per day for at least two weeks could prompt an arrhythmia (an abnormal heart rhythm) in adults 40 and older.

So is black licorice bad for you? Let's take a quick look at what the research says.

Health Benefits of Black Licorice

According to a review of the literature published in the journal Therapeutic Advances in Psychopharmacology, black licorice has been used for thousands of years in traditional Chinese, Ayurvedic, and herbal medicine. The reason it's so popular in these therapies is that licorice contains a lot of potentially healthy components, including ones that have anti-inflammatory, antioxidant, antiviral, anticancer, hepatoprotective (protects the liver), and neuroprotective (prevents nerve cell death) properties. Study authors state that licorice also appears to have antidepressant actions and can be useful for pain management.

Black licorice has also been shown to help with the symptoms that accompany metabolic syndrome, according to the authors of a 2021 review published in Advances in Experimental Medicine and Biology. Metabolic syndrome is characterized by insulin resistance, high blood pressure, high cholesterol, and excessive belly fat. This review found that black licorice seems to lower high blood sugar and high cholesterol. On the flip side, though, it tends to increase blood pressure—not good for those whose blood pressure is already on the high side.

In another 2021 review published in the journal Oxidative Medicine and Cellular Longevity, researchers took a deep dive into black licorice, what it's made up of, and what its benefits are. They found black licorice has antioxidant, antimicrobial (reduces bacteria and mold), anti-inflammatory, antiproliferative (slows or stops the spread of cells, including malignant cells, into surrounding tissues), and cytotoxic (prevents cell growth, like in the case of cancer cells) effects. In other words, it has a host of health benefits—hence, why it's been used in Chinese and Ayurvedic medicine for thousands of years.

So with all these alleged benefits of black licorice, what's up with the FDA warning? Is it really that dangerous?

The Dark Side of Black Licorice

First, it's important to note that the FDA didn't ban black licorice. According to the FDA site, black licorice is "generally regarded as safe" (GRAS) and is included on the FDA's additives list. This is because black licorice is used as a flavoring and sweetening agent in soft drinks, teas, and other consumer products. The FDA simply warned that when eaten in excess, black licorice can become toxic.

Here's why: The main component in black licorice is glycyrrhizin, a sweet compound found in licorice root. When consumed in high amounts, glycyrrhizin causes potassium levels to temporarily drop, which in turn may cause abnormal heart rhythms, high blood pressure, swelling, lethargy, and, in extreme cases, even heart failure. These issues normally go away once consumption stops.

Case in point: A 2021 study, published in the journal Deutsches Arzteblatt International, discusses one medical center that admitted six patients between 2018 and 2020 to the ICU with black licorice toxicity. All six patients were admitted with hypertension (high blood pressure), hypokalemia (low potassium), and heart arrhythmias (abnormal heart rhythms). In addition, the patients also reported muscle weakness and pain, heart palpitations, and even some paralysis. One of the patients had to be resuscitated due to a potentially fatal heart rhythm. Thankfully, all six patients recovered with the help of potassium replacement therapy in addition to a type of diuretic.

Guidelines for Black Licorice Consumption

For fans of black licorice, the FDA recommends eating it in moderation (check the label for the serving size and stick with it) and contacting your healthcare provider immediately if you experience irregular heart rhythms or muscle weakness after indulging.

Licorice also may interact poorly with certain drugs such as aspirin, oral contraceptives, and herbal supplements, so if you're taking any medications—or if you have hypertension, heart disease, or kidney disease—you may want to speak with a doctor before digging in.

According to the National Center for Complementary and Integrative Health (NCCIH), overindulging in black licorice during pregnancy has been shown to increase the chances of premature birth and problems in the baby—so it might be best to forgo it during pregnancy.

Also of note: According to the NCCIH, some candies sold in the US—including some "black licorice" candies—don't contain licorice at all. They use anise oil, which smells and tastes like black licorice.

Like many things, black licorice can probably be enjoyed in moderation. If you have a health condition that could negatively interact with it and you want to have a licorice-tasting treat, try a goodie that's flavored with anise instead. And no matter what, avoid over-indulging and keep an eye on how you feel afterward.

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